Method of forming finned tubing



Oct. 18', 1960 W. F. MATHENY EI'AL METHOD OF FORMING FINNED TUBING Original Filed Jan. v6, 1955 4 Sheets-Sheet 1 INVENTORS WILLIAM E MATHENY WILLIAM E MATHEN): JR.

ATTORNEY Oct. 18, 1960 w F. MATHENY ETAL 2,956,335

METHOD OF FORMING FINNED TUBING Original Filed Jan. 6, 1955 4 Sheets-Sheet 2 mvszyToRs WILLIAM E MATHEW) WILLIAM F MATHE/V): JR.

ATTORNEY Oct. 18, 1960 w. F. MATHENY ETAL 2,95

METHOD OF FORMING FINNED TUBING Original Filed Jan. 6, 1955 4 Sheets-Sheet :5

INVENTORS WILLIAM E MATHENY WILL/AM MAT/PIE): JR.

Bi /411x6 W ATTORNEY Oct. 18, 1960 W. F. MATHENY EI'AL METHOD OF FORMING FINNED TUBING Original Filed Jan. 6, 1955 4 Sheets-Sheet 4 INVENTORS WILLIAM E MATHENY WILLIAM E MATHE/V); JR.

ATTORNEY United States Patent METHOD OF FORNHNG FINNED TUBING William F. Matheny and William F. Matheny, Jr., Tulsa, Okla, assignors to Arrow Industrial Manufacturing Company, Tulsa, Okla, a corporation of Oklahoma Original application Jan. 6, 1955, Ser. No. 480,114. Di-

vided and this application Jan. 23, 1958, Ser. No. 710,736

Claims. (Cl. 29157.3)

This invention relates to a method of forming and shaping metal strips into edge wound spiral coils having integral flanges at their inner edges and simultaneously applying the helixes to longitudinally advancing, rotating tubes for use in the manufacture of heat exchange equipment and the like, the present application being a division of our copending application Serial No. 480,114, filed January 6, 1955, now Patent No. 2,847,055.

More particularly the invention consists in new and useful improvements in a method and apparatus for manufacturing finned tubing for heat exchangers, wherein a strip of fiat metal is continuously fed first through an edge forming device adapted to initially provide a longitudinally extending angular flange along one edge of the strip and thence between two fin forming rolls designed to flatten and stretch the opposite or non-flanged edge of the strip while simultaneously presenting the strip to the periphery of a longitudinally advancing, rotating tube.

"An object of the invention is to provide apparatus for practicing this method, having guide means associated with the fin forming rolls and adapted to present the successive convolutions of the coiling fins, to the supporting tube or core, in a non-radial plane which chordally intersects the periphery of the tube so that the flanged edge of the strip contacts the periphery of the tube under a slight radial deforming pressure from the latter which in effect, causes the edge of the fin strip to flow onto the tube, as it is wound on the tube, whereby the convol-utions of the coil are caused to firmly grip the tube and are maintained in place without the use of solder or other securing medium.

- 'Another object of the invention is to provide a finned tube forming machine which is highly adjustable to facilitate and control the action of the forming rolls and the angle of presentation of the strip to the tubes.

' A further object of the invention is to provide finned tube forming apparatus designed both for speed of operation and ease of adjustment and manipulation.

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts through the several views,

Figure 1 is a perspective view from one side of the machine.

' Figure 2 is a generally similar view in side elevation.

Figure. 3 is an enlarged detailillustrating the preferred form of edge fianging device for the strip.

.Fi gure 4 is a sectional detail of the fin forming and wrapping rolls.

jFigure' 5 is an end elevational view as seen from the left side of Figure 2 with the strip guide assembly omitted.

Figure 6 is an elevational view of the main forming roll mounting plate.

Figure 7 is a front elevation of the adjustable strip feeding assembly.

Figure 8 is a sectional view of the same, taken on line 8-8 of Figure 7.

Figure 9 is a transverse sectional view through a tube in the course of being wrapped and swedged, and

Figure 10 is an enlarged sectional view through a finned tube, taken on line 10-10 of Figure 9.

In the drawings, 10 represents a horizontal machine bed having a platform 11 at one end. The platform 11 has welded thereon an upstanding frame or support 12 which may be formed of a pair of transversely extending, side plates 13 and 14 having an end plate 15 welded between the vertical edges of the side plates at one end of the frame. opposite end of the frame are welded to a main supporting plate 16 which as seen in Figures 1 and 2, extends vertically beyond the frame 12 and laterally to one side thereof. The bottom edges of all of the plates 13, 14, 1'5 and 16 are welded to the platform 11 to form a rigid supporting structure for the various parts of the apparatus, as will hereinafter appear.

Each of the side plates 13 and 14 is provided with openings to receive a hollow shaft 17 rotatably supported by aligned bearings 18 and 19, secured to the side plates 13 and 14 respectively.

to the pulley, a gear 20 being fixed to one side of the pulley to drive the sun gear 20 of a system of planetary gears hereinafter referred to. The pulley 20 is driven by a belt 21 running from a source of motive power (not shown). The opposite end of the hollow shaft 17 carries a forming roll 22 (Figs. 2 and 4) having a beveled nose 23 which as will later appear, is adapted to cooperate with a second angularly disposed forming roll or wheel 24, in forming and applying a continuous strip of metal to a length of tubing in the fabrication of finned tubes. The forming roll 22 is longitudinally recessed as at 25 from one end, to receive the end of the hollow shaft 17 and a set screw 26 may be provided for firmly securing the roll 22 to the shaft 17, so as to rotate therewith, as will be seen from Figure 4.

The inner end of the forming roll 22 abuts the annular face of bearing 18 which serves the dual purposeof a rotary bearing for the hollow shaft 17 and an end thrust bearing for the forming roll 22.

' core of the finned tubing being fabricated, so that the annose roll 22 and the periphery of the angularly disposed nular bevelled nose 23 guides and supports the rotating and advancing tube 28 which is projected through the control bore of the hollow shaft 17. Any suitable means" may be employed for rotating and advancing the tube plishing this purpose is shown in the patent of W. F."

Matheny, No. 2,763,364, issued September 18, 1956.-

The complementary forming wheel 24 is carried at one end of a shaft 32 rotatably supported in bearings 33 and 340m an adjustable supporting plate 35. As seen in Figures 4 and 5, the forming wheel 24 is in the form of solid circular disc having its under face dished out as at 24*, to accommodate the radial fins which have been formed and applied to the tube 28 by the action of the Patented Oct. 18, 1960 i The edges of the side plates 13 and 14 at the A drive pulley 20 runs on a" bearing which is pressed on shaft 17 and suitably secured forming roll 24, as will be described later on. The supporting plate 35 is hingedly mounted at one vertical edge, by means of a shaft 36 welded to the edge of the plate 35 and projecting vertically beyond the upper and lower extremities thereof, where it is rotatably embraced by bearings 37 and 38, bolted to the fixed supporting. plate 16 of the mainsupporting frame 12. As seen in Fignlre 2, where only the bearing 37 is shown, the fixed plate .16 is slotted as at 39 to receive the bearing bolts 40, whereby the bearing 37 is adjustable laterally in a plane parallel to the plate 16. This same arrangement is provided for the lower bearing 38 and the bearings 37 and 38 are preferably'of the universal type to provide for minute adjustment of the angular position of the forming wheel.24 with respect to the. forming nose 23, by manipulation of the bearings 37 and 38, to change the angle of the axis of the shaft 36 with respect to the axis of the hollow shaft, 17 and the forming nose 23. To facilitate the ad.- justment of the shaft 36and bearings 37 and 38, a set screwarrangement 41, fixed to one end of the housing of bearing 37, as at 42, passes through a lug 43 secured to the plate 16. Lock nuts 44 retain the set screw 41 in adjusted position.

The hinged plate 35 carrying the forming wheel 24 and its shaft 32, is adjusted by the means just described, to regulate the angle of contact of the periphery of the wheel 24 With the nose 23 of the forming roll 22, so that as the ribbon 45 passes between the two forming elements, the degree of deformation of the strip. can be predetermined. In other words, as will later appear, it is desirable to subject the outer edge of the fin strip 45 to a deforming or flattening pressure as it passes betweenthe forming elements, so as to stretch the outer edge and cause the strip' to curve around the axisof the tube 28 in the form of a helix. Thus, the angle of contact between the periphery of the:forming wheel 24 and the nose 23 is such that the periphery of said Wheel 24 lies more closely to the outer edge of the frusto-conical nose 23, than to the inner edge thereof. Obviously, by increasing the proximity of the adjacent peripheries of the forming elements toward the outer extremity of the nose 23, the resulting curve or curling of the fin is rendered more acute to determine the ultimate shape of the ribbon as it is presented to the tube 28 and wrapped thereon.

After this angle of contact has been set, the hinged plate 35 is maintained in locked position by a lock bolt 46 which extends through a fixed lug 47, attached to the edge of the plate 35, with its other end engaging a lug 48 fixed to the plate 15 of the supporting frame 12. The lock bolt 46 is threaded to receive a nut 49 by means of which the pressure of the forming wheel 24 against the forming nose 23, may be governed. Obviously, this hinge arrangement also permits the plate 35 and the elements supported thereby, to be retracted from the tubing being worked upon.

The metal strip 45 is fed from a reel (not shown) and before entering between the forming elements 22 and 24, is preformed with a longitudinal flange or substantially right angular leg along one edge so as to provide a base for supporting the fin on the tube 28. The preforming mechanism consists of a pair of complementary guide rolls 50 and 51, respectively mounted'on shafts 52 and 53, rotatably supported in bearings 54 and 55. The bearings 54 and 55 are bolted to the front plate 56 of a bracket 57, bolted to the plate 15 of frame 12 as at 58 in Figure 2. A slot arrangement 59 cooperates with the bolts 58 to permit the adjustment of the bracket 57 to align the performing mechanism 5051 with the strip feeding guide to be described.

Although various forms, of preforming mechanisms may be employed, the arrangement shown in Figure 3 has proven satisfactory. Here it will be seen that the main roll 50 is provided with a peripheral recess 60 of a transverse dimension to receive the periphery of the complementary roll, 51. The latter is provided with an annular recess 61 at its lower edge, shaped to accommodate a radial inclined ridge 62 at one side of the recess 60 in the roll 50, with sufficient clearance therebetween to permit the lower edge of the strip 45 to be bent at an angle into the recess 61, thus forming a foot or base flange 63, along the lower edge of the strip 45 as the strip leaves the preforming rolls. It will be seen in Fig. 3 that the width of the recess 68 is the same as that of the unbent strip 45 and there is just sufiicient clearance between the lateral margins of the recess and the lateral'edges of the roll 51 to receive the latter with a running fit. Thus, the roll 51 is kept vertically centered in recess 69 of roll 50, to prevent the strip from being cut as the flange 63 is being turned. The inclined ridge 62 facilitates the bending operation by making it more gradual.

Turning now to the strip feeding assembly shown in detail in Figures 7 and 8, itwill be seen that a guide plate 64 forms the means for presenting the strip 45 t0 the forming elements 2224, after leaving the preform: ing rolls 50-51, which are located anterior to the feeding device. The guide plate 64 consists of an elongated plate having an arcuate edge 65 on one side bounded by a pair of parallel spaced guide flanges 66 between which the strip 45 passes over the arcuate surface. The feeding end of the plate 64 terminates in a reduced tapering nose 67 which forms a continuation of the arcuate edge 65 and is adapted to be positioned so as to properly direct the strip 45 between the forming elements 22 and 24.

It is important to the proper operation of this apparatus, that the guide plate 64 be capable of adjustment in three different planes. In other words, it must be adjustable in a substantially vertical plane toward and away from the axis of the tube 28 on which the strip is being wound, to control the elevation of the feeding nose 67 with respect to the tube 28. It must be rotatably adjustable about a substantially vertical axis to control the distance of the nose 67 from the tube 28 and it must be rotatably adjustable about a horizontal axis to regulate the angle of presentation of the strip 45 to the tube 28.

This latter adjustment is to facilitate the proper feeding of the strip 45 onto the tube 28 in a non-radial plane which chordally intersects the periphery of the tube so that the flanged edge 63 of the strip contacts the periphery of the tube under a slight radial deforming pressure from the latter which as previously stated, causes the edge of the fin strip to be deformed laterally and flow on to the.

tube.

This triple adjustment is accomplished by mounting the strip feeding assembly on a supporting bar 68, slidably mounted in a guide block 69 which is welded to the supporting plate 35 as will be seen in Figures 1 and 2. The supporting bar 68 is adjustable longitudinally, by means of a screw threaded member 70 secured to the upper end of the bar and projecting through a bracket 71 welded to and projecting laterally from the plate 35 and after the proper longitudinal adjustment is made, lock bolts 72 and 73 are screwed into engagement with the intervening bracket 71.

The lower end of the supporting bar 68 carries an intermediate connecting link 74 which is offset and pivotally mounted on one side of the bar 68, by a horizontal pivot 75 and extends downwardly into abutting relation with a mounting strip 76 which, together with the guide plate 64 is pivotally mounted on the lower end of the link 74 by a vertical pivot bolt 77 which extends through both the plate 64 and the strip 76 and into the lower end of the link 74, as seen in Figure 7. A lock screw 78 ex tending through the plate 64 and into the strip 76 prevents rotary movement of the latter relative with the plate 64.

Adjustment of the guide assembly about the horizontal axis 75 is accomplished by means of two opposed adjusting screws 79 extending through complementary threaded ears 80 welded to opposite sides of the supporting bar 68, with their inner ends in abutting relation to an intervening lug 81, formed integrally with and projecting: up-

wardly from the link 74. Thus, by manipulating the adjusting screws 79 to force the lug 81 either in one direction or the other, the link 7 and the assembly suspended therefrom, is caused to describe an arc about the axis 75 to either elevate or lower the nose 67 of the guide plate 64.

A generally similar arrangement is employed for e fecting the adjustment of the feeding assembly about the vertical axis 77. As seen in Figure 8, -a pair of adjusting screws 82 are supported in opposed relation by a pair of spaced ears 83 welded to opposite sides of the link 74. The inner ends of the screws 82 abut an upstanding lug 84 which is welded to the upper face of the strip 76 and is interposed between the screws 82. ulating the screws 82, the lug 84, the strip 76 and the guide plate 64 are rotated about the axis 77 to control the proximity of the nose 67 with respect to the tube 28.

With the guide plate 64 and its nose 67 properly adjusted, the fin strip 45, with its preformed base flange 63, is fed between the forming roll 22 and forming wheel 24, with the flanged edge 63 advancing into engagement with the tube 28 in a non-radial plane which intersects the periphery of the tube 28 as shown in Figure 9. The action of the forming roll and wheel flattens and stretches the outer edge 85 of the strip 45, causing the strip to coil about the tube 28 as the opposite flanged edge 63 of the strip is being slightly radially deformed and caused to flow on to the tube 28 winch is continuously rotating and advancing through the hollow shaft 17 carrying the nose roll 22. The result of this operation is a tight binding of the flanged edge 63 of the strip on to the tube 28 which avoids the necessity of soldering or other securing medium.

However, in order to provide a more effective gripping action and to produce a more finished product, it is desirable to employ a swedging roll which engages the base flange 63 of the advancing convolutions of the coil and presses it firmly into engagement with the tube 28. This swedging roll consists of a pair of parallel discs 86 spaced on a horizontal axle 87 a sufficient distance to accommodate the fin strip 45. The axle 87 is rotatably mounted in a bearing 88 carried at the upper end of a vertical rod 89, which is reciprocably mounted in a support 90 secured to and projecting upwardly from the platform 11, as seen in Figures 2 and 5. A longitudinal slot 91 in the periphery of the rod 89 engages a key within the support 90 to prevent rotation of the rod 89 and displacement of the swedging rolls 86.

The swedging roll 86 is maintained under a spring tension in its engagement with the fin tube and is retractable from the latter by means of a releasable mechanism shown in Figures 2 and 5. A pair of spaced cross arms 92 are pivotally mounted at one end as at 93, on an intervening vertical leg 94, said cross arms having pivoted between their opposite ends a latch member 95 having a handle 96. A second vertical leg 97 also extending from the platform 11, has a notch 98 for engagement by the latch 95. A grip 99 is fixed to the end of the cross arms 92 of the assembly for elevating the arms into locked position. The swedging roll supporting rod 89 extends between the spaced cross arms 92 and has fixed thereto an abutment 100 which is also secured to the undersides of the cross arms 92. Between the abutment 100 and a collar 101, spaced upwardly on the rod 89, is a coil spring 102 which, when the cross arms 92 are in their upper or locked position, causes a spring tension on the rod 89, forcing the same upwardly and with it the swedging roll 96. When it is desired to release the swedging roll from the tube 28, the operator trips the handle 96 upwardly, releasing the latch 95 from the notch 98 which permits the cross arms 92 and with them the rod 89 and swedging roll 86, to be lowered. The elements are returned to operative position by simply lifting the grip 99 until the latch 95 engages the notch 98.

It will thus be seen that in operation, as the constantly Thus, by maniprotating and advancing tube 28 emerges-from the bore of the forming roll 22, the preflanged strip 45 is presented to the periphery of the tube and between the periphery of the forming wheel and the nose 23 of the forming roll. The upper edge of the strip is flattened and stretched to form a coil about the tube 28 and as previously explained, the flanged edge of the strip being presented in a non-radial plane which chordally intersects the periphery of the tube, it is laterally deformed by the tube and caused to firmly grip the tube during its advance. The flanged edge is then swedged on to the tube by the swedging rolls 86 to progressively complete the formation and wrapping of the convolutions of the coiled fin tube. As a result of this operation there is provided a very rigid fin tube structure wherein the base of the fins is firmly supported all along the tube without the need of additional securing means such as solder, etc.

By means of the triple adjusting mechanism for the feeding plate 64, the most minute adjustment is made possible to facilitate the use of different materials and to regulate the pitch of the convolutions of the coiled fin.

It is to be noted that the present invention is primarily designed for the manufacture of flat or smooth helical finned tubing, as distinguished from the corrugated types and the relationship of the forming wheel to the forming nose is such as to enable the simultaneous forming and winding of a minute fin on extremely small tubing. Considerable difficulty has been encountered in the past, in the manufacture of finned tubing of small diameter such as is required in the fabrication of automotive radiators and the like. However, with the present invention, by employing a hollow guide shaft having protruding therefrom a substantially frusto-conical smooth forming nose with a coaxial opening to receive the advancing tubing, and arranging the complementary forming wheel on an inclined fixed axis which intersects the axis of the hollow shaft so that the periphery of the wheel is directly opposed to the periphery of the nose, a fin of extremely small radial extent may be formed.

From the foregoing, it is believed that the invention may be readily understood by those skilled in the art, without further description, it being home in mind that numerous changes may be made in the details of structure without departing from the spirit of the invention as set forth in the following claims.

What we claim is:

1. In a method of making finned tubing by spirally winding a strip of metal on a continuously rotating and advancing tube, the step comprising longitudinally feeding said strip edgewise, to the periphery of said tube, with its base edge progressing in a transverse, non-radial plane which chordally intersects the periphery of said tube, while stretching the opposite edge of said strip to form a helical fin, and, with the periphery of the tube acting as a mandrel, laterally deforming the base edge of said strip by progressive contact with and radial force from said tube, to tightly embrace the latter.

2. In a method of making finned tubing by spirally winding a strip of metal on a continuously rotating and advancing tube, the steps comprising forming an angular longitudinally extending flange on the base edge of said strip, and longitudinally feeding said strip edgewise; to the periphery of said tube, with said flange progressing in a transverse, non-radial plane which chordally intersects the periphery of said tube, while stretching the opposite edge of said strip to form a helical fin, and, with the periphery of the tube acting as a mandrel, laterally deforming said flange and base edge of the strip by progressive contact with and radial force from said tube, to tightly embrace the latter.

3. In a method of making finned tubing by spirally winding a strip of metal on a continuously rotating and advancing tube, the steps comprising longitudinally feeding said strip edgewise, to the periphery of said tube, with its base edge progressing in a transverse, nonradial plane which chordally intersects the periphery of said tube, while stretching the opposite edge of said strip-to form a helical tin, and, with the periphery of the tube acting as a mandrel, laterally deforming the base edge of said strip by progressive contact with and radial force from said tube, to tightly embrace the latter, and swedging said deformed base on the periphery of said tube;

4. In a method of making finned tubing by spirally winding a strip of metal on a continuously rotating and advancing tube, the steps comprising forming an angular longitudinally extending flange on the base edge of said strip, feeding said strip edgewise, to the periphery of said tube, with said flange progressing in a transverse, non-radial plane which chordally intersects the periphery of said tube, while stretching the opposite edge of said strip to form a helical fin, and, with the periphery of the tube acting as a mandrel, laterally deforming said flange and base edge of said strip by progressive contact with and radial 'force from said tube, to tightly embrace the latter, and swedging said flanged base edge on the periphery of said tube.

5. The method as claimed in claim 4, wherein the respective steps are sequentially performed in a continuous operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,992,297 Dewald Feb. 26, 1935 2,151,685 Berg Mar. 28, 1939 2,437,500 Bruegger Mar. 9, 1948 

